package keypair;

//----------------------------------------------------------------------------
//$Id: IKeyPairCodec.java,v 1.2 2005/10/06 04:24:16 rsdio Exp $
//
//Copyright (C) 2001, 2002, Free Software Foundation, Inc.
//
//This file is part of GNU Crypto.
//
//GNU Crypto is free software; you can redistribute it and/or modify
//it under the terms of the GNU General Public License as published by
//the Free Software Foundation; either version 2, or (at your option)
//any later version.
//
//GNU Crypto is distributed in the hope that it will be useful, but
//WITHOUT ANY WARRANTY; without even the implied warranty of
//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
//General Public License for more details.
//
//You should have received a copy of the GNU General Public License
//along with this program; see the file COPYING.  If not, write to the
//
// Free Software Foundation Inc.,
// 51 Franklin Street, Fifth Floor,
// Boston, MA 02110-1301
// USA
//
//Linking this library statically or dynamically with other modules is
//making a combined work based on this library.  Thus, the terms and
//conditions of the GNU General Public License cover the whole
//combination.
//
//As a special exception, the copyright holders of this library give
//you permission to link this library with independent modules to
//produce an executable, regardless of the license terms of these
//independent modules, and to copy and distribute the resulting
//executable under terms of your choice, provided that you also meet,
//for each linked independent module, the terms and conditions of the
//license of that module.  An independent module is a module which is
//not derived from or based on this library.  If you modify this
//library, you may extend this exception to your version of the
//library, but you are not obligated to do so.  If you do not wish to
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//----------------------------------------------------------------------------

import java.security.PrivateKey;
import java.security.PublicKey;

/**
* <p>The visible methods of an object that knows how to encode and decode
* cryptographic asymmetric keypairs. Codecs are useful for (a) externalising
* public and private keys for storage and on-the-wire transmission, as well as
* (b) re-creating their internal Java representation from external sources.</p>
*
* @version $Revision: 1.2 $
*/
public interface IKeyPairCodec {

// Constants
// -------------------------------------------------------------------------

/** Constant identifying the <i>Raw</i> encoding format. */
int RAW_FORMAT = Registry.RAW_ENCODING_ID;

// Method(s)
// -------------------------------------------------------------------------

/**
 * <p>Returns the unique identifier (within this library) of the format used
 * to externalise public and private keys.</p>
 *
 * @return the identifier of the format, the object supports.
 */
int getFormatID();

/**
 * <p>Encodes an instance of a public key for storage or transmission purposes.</p>
 *
 * @param key the non-null key to encode.
 * @return a byte sequence representing the encoding of the designated key
 * according to the format supported by this codec.
 * @exception IllegalArgumentException if the designated key is not supported
 * by this codec.
 */
byte[] encodePublicKey(PublicKey key);

/**
 * <p>Encodes an instance of a private key for storage or transmission purposes.</p>
 *
 * @param key the non-null key to encode.
 * @return a byte sequence representing the encoding of the designated key
 * according to the format supported by this codec.
 * @exception IllegalArgumentException if the designated key is not supported
 * by this codec.
 */
byte[] encodePrivateKey(PrivateKey key);

/**
 * <p>Decodes an instance of an external public key into its native Java
 * representation.</p>
 *
 * @param input the source of the externalised key to decode.
 * @return a concrete instance of a public key, reconstructed from the
 * designated input.
 * @exception IllegalArgumentException if the designated input does not
 * contain a known representation of a public key for the format supported by
 * the concrete codec.
 */
PublicKey decodePublicKey(byte[] input);

/**
 * <p>Decodes an instance of an external private key into its native Java
 * representation.</p>
 *
 * @param input the source of the externalised key to decode.
 * @return a concrete instance of a private key, reconstructed from the
 * designated input.
 * @exception IllegalArgumentException if the designated input does not
 * contain a known representation of a private key for the format supported
 * by the concrete codec.
 */
PrivateKey decodePrivateKey(byte[] input);
}
